Modern wireless communication multifunctioning microwave circuits provide filter and antenna characteristics or filter and divider characteristics simultaneously with compact and flexible electrical characteristics. Metamaterial (MTM) filtering circuits provide filtering antenna (FA) response while simultaneously having a small structural footprint, flat gain in passband, exceptional radiation null, and excellent out-of-band rejection. This chapter includes the strategy and study of compact, planar FAs with the help of composite right/left-handed MTM structures. An asymmetric coplanar waveguide feeding approach with the aid of a circular interdigital capacitor, a meander line, and rectangular patches was first used to create a small dual-band FA. The L-shaped patch, which serves as a radiating element, was used to construct the FA structure in place of a rectangular patch and coupling at the load side. The proposed FA has two radiation nulls and two passbands. The dispersion diagram of the developed filter provides evidence of its MTM features. Another, compact and reasonably priced, planar filtenna with printed structure includes an inverted L antenna, an admittance inverter-linked line, and a folded half-wavelength resonator. It has properties that make it ideal for Wi-Fi applications, including a consistent and constant emission pattern, small cross-polarization, sharp edges at both bands, a fractional bandwidth of 7.5%, and strong stopband characteristics. In the projected working frequency passband, the antenna is incorporated to filter over and done with a coupled line admittance inverter to create a small segment with almost very low insertion loss. The filter antenna has a uniform radiation pattern omnidirectional in the H-plane and in the E-plane provides monopole pattern, as well as a steep skirt at both edges. Plotting a dispersion diagram of the suggested structure allows one to identify the MTM properties.